1. Field of the Invention
The present invention relates to a rotation transmission buffer apparatus composed of an input rotary body, an output rotary body and an elastic body provided therebetween and, more particularly to a rotating transmission buffer apparatus which has a simpler structure and in which the durability of the elastic body is improved.
2. Description of the Related Art
A conventional rotation transmission buffer apparatus composed of an input rotary body, an output rotary body and an elastic body provided therebetween absorbs the inertia force of, for example, a motor when a window of an automobile is raised or lowered by the turning force of the motor, by deforming a cylindrical rubber member as the elastic body, thereby preventing the breakage of the gear provided on the output rotary body.
A rotation transmission buffer apparatus shown in FIGS. 4 and 5 has been proposed. In FIGS. 4 and 5, the reference numeral 1 represents an annular input rotary body. A multiplicity of teeth 1A are provided on the outer peripheral surface of the input rotary body 1 so as to mesh the gear (not shown) on the output shaft of a motor (not shown), and a plurality of substantially T-shaped notches 1B are formed on the inner peripheral surface of the input rotary body 1.
The reference numeral 2 represents an elastic body made of rubber, for example. The elastic body 2 is composed of a cylindrical portion 2A and a plurality of substantially T-shaped joint arms 2B which are integral with and project radially from the cylindrical portion 2A.
The reference numeral 3 represents a cylindrical output rotary body. An output shaft 4 is joined to the center of the output rotary body 3 by a bolt 5, and the inner peripheral surface of the cylindrical portion 2A of the elastic body 2 is bonded to the outer peripheral surface of the output rotary body 3 by, for example, vulcanizng adhesion.
The rotation transmission buffer apparatus having the above-described structure is assembled by fitting the plurality of substantially T-shaped joint arms 2B which are integral with and project radially from the cylindrical portion 2A of the elastic body 2 into the plurality of substantially T-shaped notches 1B formed on the inner peripheral surface of the input rotary body 1.
According to this structure, the turning force of the motor (not shown) is transmitted to the teeth 1A of the input rotary body 1 so as to rotate the input rotary body 1. The turning force of the input rotary body 1 rotates the elastic body 2 and the output rotary body 3 through the substantially T-shaped joint arms 2B of the elastic body 2 which are fitted into the plurality of substantially T-shaped notches 1B formed on the inner peripheral surface of the input rotary body 1.
The conventional rotation transmission buffer apparatus, however, is disadvantageous in that since the inner peripheral surface of the cylindrical portion 2A of the elastic body 2 is bonded to the outer peripheral surface of the output rotary body 3 by vulcanizng adhesion, a crack is formed in the cylindrical portion 2A due to a repeated fatigue and a change with time or the cylindrical portion 2A comes out due to a reduction in the adhesion strength, and in that since the shapes of the substantially T-shaped notches 1B of the input rotary body 1 and the substantially T-shaped joint arms 2B of the elastic body 2 are complicated, a large number of machining and assembling steps are necessary.